Pentair 8.5" Triton C and C-3 Buttress Thread Lid Closure for Triton C Sand Filter

The Pentair 8.5" Triton C and C-3 Buttress Thread Lid Closure Kit (part number 154856) is a heavy-duty, commercial-grade replacement dome enclosure assembly engineered specifically for high-capacity Triton C and Triton C-3 side-mount commercial pool and spa sand filtration systems, such as the TR100C and TR140C models. Injection-molded from a thick, glass-reinforced structural polymer composite in a sleek black finish, this wide-diameter closure assembly features deep, coarse 8.5-inch buttress threading designed to spin directly onto the structural top neck of the fiberglass sand filter shell. Its primary operational and structural role is to form an absolute airtight and watertight pressure seal over the filter's top service access hatch, ensuring the vessel can safely contain continuous, high-velocity hydraulic water flows and intense internal operating pressures up to 50 PSI without weeping, spraying, or experiencing dangerous blowouts. Typically packaged as a comprehensive kit that includes the rigid threaded closure dome, an air-bleed assembly port, and a matching thick-walled compression O-ring, it is built to withstand extreme outdoor UV exposure, chemical degradation from commercial sanitizers like chlorine, and routine servicing tool torque. Because of its large 8.5-inch span and thick, reinforced plastic architecture required for high-pressure commercial safety margins, the complete lid closure assembly carries an individual product and shipping weight of approximately 3.08 to 5.00 pounds depending on whether additional air-relief hardware extensions are pre-installed in the box.